Background: Social difficulties are inherent to social anxiety and are critical in depression. A key feature in both disorders is social avoidance, which leads to the loss of opportunities and precludes from improving social abilities. The need for studying social functioning using interactive tasks that immerse the subject in a social context has been highlighted. Methods: We developed an interactive task that allows measuring social avoidance. In each round, participants choose between two categories of co-players, with which kind of partner they would like to make a team. In material terms, it is always better to choose the high-category option. However, this maximizes chances for being the worst player in the team, which relates to upward social comparison and guilt. Participants with varied levels of depression and social anxiety symptoms performed this task. Results: The higher the depression and social anxiety symptoms, the more that participants avoided the highcategory partners, the lower the number of points earned and the higher the negative emotions (guilt, nervousness, shame) reported about having to play with a co-player, with this effect becoming more accentuated as the rank of the co-player increased. Limitations: The study sample was restricted to university students and included mostly women. Conclusions: This work provides a tool for studying social avoidance through an interactive set-up and contributes to the understanding of this behavior in mental health.